Weak Charge Transfer Research Articles

9,10-Bis(5H-dibenzo[b,f]azepino)anthracene

The title compound with a donor–π–donor (D–π–D) type triad structure was synthesized by Buchwald–Hartwig amination using 9,10-dibromoanthracene and 5H-dibenzo[b,f]azepine, and characterized by 1H, 13C{1H} NMR, HRMS, and X-ray diffraction analysis. The azepine–anthracene–azepine units are nearly orthogonal to each other, with a torsion angle of 88°. A broad and weak absorption band around 410–480 nm and the low emission character (ΦF = 0.01) suggest the weak intramolecular charge transfer from the azepine to the anthracene unit due to the twisted structure.

Exploring charge transfer and schottky barrier modulation at monolayer Ge2Sb2Te5-metal interfaces

Monolayer Ge2Sb2Te5exhibits great potential in non-volatile memory technology due to its excellent electronic properties and phase-change characteristics, while the fundamental nature of Ge2Sb2Te5-metal contacts has not been well understood yet. Here, we provide a comprehensiveab initiostudy of the electronic properties between monolayer Ge2Sb2Te5and Pt, Pd, Au, Cu, Cr, Ag, and W contacts based on first-principles calculations. We find that the strong interaction interfaces formed between monolayer Ge2Sb2Te5and Pt, Pd, Cr, and W contacts show chemical bonding and strong charge transfer. In contrast, no apparent chemical bonding and weak charge transfer are observed in the weak interaction interfaces formed with Au, Cu, and Ag. Additionally, our study reveals the presence of a pronounced Fermi level pinning effect between monolayer Ge2Sb2Te5and metals, with pinning factors ofSn=0.325andSp=0.350. By increasing the interlayer distance, an effective transition fromn-type Ohmic contact ton-type Schottky contact is facilitated because the band edge of Ge2Sb2Te5is shifted upwards. Our study not only provides a theoretical basis for selecting suitable metal electrodes in Ge2Sb2Te5-based devices but also holds significant implications for understanding Schottky barrier height modulation between semiconductors and metals.

Role of electron withdrawing moieties in phenoxazine–oxadiazole-based donor–acceptor compounds towards enriching TADF emission

Herein, we reported the effect of electron withdrawing units, such as trifluoromethyl (CF3) and cyanide (CN), substitution on a thermally activated delayed fluorescent (TADF) molecule (10-(4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl)-10H-phenoxazine (PXZ-OXD)). The addition of electron withdrawing units has increased the acceptor strength and reduced the interaction between PXZ and OXD, thus reducing the gap between the singlet and triplet states (ΔEST) of excitons. To understand the variation in the acceptor strength of PXZ-OXD as a function of its molecular structure and density of states, density functional theory (DFT) and time-dependent DFT (TDDFT) were conducted. Transition density matrix investigations revealed that the addition of −CF3 and –CN to PXZ-OXD triggers CT excitons, while inducing lower ΔEST values. Particularly, the lowest ΔEST (0.05 eV) with a notable red shift in the emission spectrum was observed with 4′-CF3PXZOXD. The delayed component lifetime of PXZOXD is found to be reduced after the substitution of −CNwhm and −CF3. Despite the weak charge transfer transitions, the substitution of conjugative –CN group is found to be beneficial in improving the HOMO-LUMO overlap with a moderate decrease in reverse intersystem crossing (KRISC), which attained enhancement in the photoluminescent quantum yield. Additionally, the substitution of the above electron withdrawing units on PXZ-OXD yielded a red shift in the electroluminescence spectrum. Furthermore, the external quantum efficiency (at 100 cd/m2, i.e., EQE100) of the 4′-CNPXZOXD-based organic light-emitting diode is found to improve by 21.13 % against the PXZOXD (16.9 %).

Structural Fine-Tuning to Achieve Highly Fluorescent Organic and Water-Soluble Thiazolo[5,4-d]thiazole Chromophores.

Fluorescent molecular systems are important for various applications such as sensing of analytes, probes for biologically relevant processes and as optoelectronic materials. Achieving high fluorescence quantum yield across the spectrum of solvent polarity and in solid-state is challenging in molecular materials. Herein, we present a strategy to achieve strongly fluorescent molecular materials based on weak intramolecular charge-transfer (ICT) in a family of unsymmetrical donor-thiazolo[5,4-d]thiazole-acceptor systems (both neutral and cationic). Detailed photophysical studies reveal that the delicate balance between the donor and acceptor result in high solution-state fluorescence quantum yield (>80 %) in both polar protic and apolar solvents. Quantum chemical computations uncover a hitherto unappreciated insight that the extent of ICT is aptly represented by the change in Mulliken charges between the ground and excited state for different fragments rather than the classical approach of monitoring the change in dipole moment for the entire molecule. This insight rationalizes the observed photophysical properties and can have implications in the design of tuneable donor-π-acceptor systems.

How the addition of atomic hydrogen to a multiple bond can be catalyzed by water molecules.

Observational data show complex organic molecules in the interstellar medium (ISM). Hydrogenation of small unsaturated carbon double bond could be one way for molecular complexification. It is important to understand how such reactivity occurs in the very cold and low-pressure ISM. Yet, there is water ice in the ISM, either as grain or as mantle around grains. Therefore, the addition of atomic hydrogen on double-bonded carbon in a series of seven molecules have been studied and it was found that water catalyzes this reaction. The origin of the catalysis is a weak charge transfer between the π MO of the unsaturated molecule and H atom, allowing a stabilizing interaction with H2O. This mechanism is rationalized using the non-covalent interaction and the quantum theory of atoms in molecules approaches.

M(TEIM) complexes with M as Co and Fe: Analogues of classic M(TIM)

The syntheses and characterization of Fe and Co complexes supported by a new tetra-imine macrocycle, TEIM (2,3,9,10-tetraethyl-1,4,8,11-tetraazacyclotetradeca-1,3,8,10-tetraene), are reported. Templating with Co(OAc)2·4H2O yielded trans-[Co(TEIM)Cl2][PF6] (1a), which was converted to trans-[Co(TEIM)X2][PF6] (X = N3 (2a) and NO2 (3a)) through reactions with NaX (X = N3 or NO2). Templating with Fe generated trans-[Fe(TEIM)(NCCH3)2][PF6]2, which was oxidized to trans-[Fe(TEIM)Cl2][PF6] (1b). The reaction of 1b with NaN3 formed [Fe(TEIM)(N3)2][PF6] (2b) while the reaction with [Fe(TEIM)(NCCH3)2][PF6]2 and NaNO2 yielded trans-[Fe(TEIM)(NO2)2] (3b). Single crystal X-ray diffraction studies revealed a pseudo-octahedral geometry around the Co / Fe centers with the ethyl groups oriented above or below the plane of the TEIM ring. The absorption spectra of 1b displays weak charge transfer bands near the UV to visible region, while 2b and 3b displayed intense charge transfer bands within the visible region. Cyclic voltammograms of 1a revealed four 1 e− reductions while those of 2a and 3a display only three cathodically shifted reductions. Analogous studies of 1b and 2b revealed two 1 e- reductions while 3b displays only an oxidation event. EPR studies of ferric complexes 1b and 2b indicated a low spin d5 electronic figuration with S = ½ ground state.

Precisely Controlling Polymer Acceptors with Weak Intramolecular Charge Transfer Effect and Superior Coplanarity for Efficient Indoor All-Polymer Solar Cells with over 27% Efficiency.

Indoor photovoltaics (IPVs) are garnering increasing attention from both the academic and industrial communities due to the pressing demand of the ecosystem of Internet-of-Things. All-polymer solar cells (all-PSCs), emerging as a sub-type of organic photovoltaics, with the merits of great film-forming properties, remarkable morphological and light stability, hold great promise to simultaneously achieve high efficiency and long-term operation in IPV's application. However, the dearth of polymer acceptors with medium-bandgap has impeded the rapid development of indoor all-PSCs. Herein, a highly efficient medium-bandgap polymer acceptor (PYFO-V) is reported through the synergistic effects of side chain engineering and linkage modulation and applied for indoor all-PSCs operation. As a result, the PM6:PYFO-V-based indoor all-PSC yields the highest efficiency of 27.1% under LED light condition, marking the highest value for reported binary indoor all-PSCs to date. More importantly, the blade-coated devices using non-halogenated solvent (o-xylene) maintain an efficiency of over 23%, demonstrating the potential for industry-scale fabrication. This work not only highlights the importance of fine-tuning intramolecular charge transfer effect and intrachain coplanarity in developing high-performance medium-bandgap polymer acceptors but also provides a highly efficient strategy for indoor all-PSC application.

Photoactive cationic conjugated microporous polymers containing pyrimidine with an ‘adsorption-kill’ antibacterial strategy for infected wound healing

Pathogenic bacterial invasion leads to severe inflammation that hinders wound healing, and it has become a major medical threat worldwide. Photodynamic therapy (PDT) has emerged as a promising strategy for treating microbial infection; however, developing a dressing with PDT effect and excellent biological functions poses a formidable challenge. Herein, a novel cationic pyrimidine-modified conjugated microporous polymer, BPyMe-CMP, was rationally designed and synthesized via a Sonogashira-Hagiwara and SN2 substitution reaction. The BPyMe-CMP exhibited weak interfacial charge transfer resistance and demonstrated superior photoinducible carrier separation, thereby displaying an excellent photoelectric response. Consequently, the BPyMe-CMP could readily generate reactive oxygen species under visible light irradiation to kill bacteria. In addition to enhancing the photogenerated electron transfer process, BPyMe-CMP also provided abundant attraction sites for bacteria to reinforce the antibacterial ability. The deposition of BPyMe-CMP onto polyvinyl alcohol-modified silk fibroin (SF/PVA) film served as a wound dressing to promote healing. The in vitro and in vivo experiments revealed that the SF/PVA@BPyMe-CMP induced M2-type macrophage polarization, promoted L929 fibroblast migration, exhibited bactericidal activity, and induced angiogenesis, which synergistically accelerated the healing of methicillin-resistant Staphylococcus aureus-infected wounds. This study provides data support to advance the construction of a multi-functional wound dressing based on pyrimidination and cationization for the treatment and rapid healing of infected wounds.

Constructing multifunctional deep-blue emitters with weak charge transfer excited state for high-performance non-doped blue OLEDs and single-emissive-layer hybrid white OLEDs

Deep-blue emitter with high photoluminescence efficiency (PLQY) is highly desirable in ultra-high definition displays and white solid-state lightings. In this work, two deep-blue phenanthro[9,10]imidazole derivatives, PPIS and PPPIS, with hot exciton property are successfully developed. Compared to PPIS, the embedded phenyl bridge in PPPIS is able to effectively increase the overlap of frontier molecular orbitals. In consequence, PPPIS shows higher oscillator strength and significantly enhanced PLQY. PPPIS also achieves better electroluminescence performance in non-doped device, showing deep-blue emission with Commission International de l'Eclairage (CIE) coordinates of (0.153, 0.087) and the maximum external quantum efficiency (EQEmax) of 8.5% with minuscule efficiency roll-off. Meanwhile, when PPPIS serves as the host for phosphor PO-01, high-efficiency orange phosphorescent device is obtained with high EQEmax of 29.8% and negligible efficiency roll-off at 1000 cd/m2. Further, efficient single-emissive-layer white device is assembled via utilizing PPPIS as a blue emitter as well as the host for PO-01 simultaneously, providing warm-white emission with CIE coordinates of (0.429, 0.433) at 1000 cd/m2, the forward-viewing EQEmax of 27.2% and maximum power efficiency (PEmax) of 80.1 lm/W, respectively. Our studies can establish a viable design strategy for deep-blue emitters in high-performance non-doped blue OLEDs and hybrid WOLEDs.

Intermolecular donor-acceptor stacking to suppress triplet exciton diffusion for long-persistent organic room-temperature phosphorescence.

Controlling triplet states is crucial to improve the efficiency and lifetime of organic room temperature phosphorescence (ORTP). Although the intrinsic factors from intramolecular radiative and non-radiative decay have been intensively investigated, the extrinsic factors that affect triplet exciton quenching are rarely reported. Diffusion to the defect sites inside the crystal or at the crystal surface may bring about quenching of triplet exciton. Here, the phosphorescence lifetime is found to have a negative correlation with the triplet exciton diffusion coefficient based on the density functional theory (DFT)/time-dependent density functional theory (TD-DFT) calculations on a series of ORTP materials. For systems with a weak charge transfer (CT) characteristic, close π-π stacking will lead to strong triplet coupling and fast triplet exciton diffusion in most cases, which is detrimental to the phosphorescence lifetime. Notably, for intramolcular donor-acceptor (D-A) type systems with a CT characteristic, intermolecular D-A stacking results in ultra-small triplet coupling, thus contributing to slow triplet diffusion and long phosphorescence lifetime. These findings shed some light on molecular design toward high-efficiency long persistent ORTP.

Improved Conductivity and in Situ Formed Heterojunction via Zinc Doping in CuBi2O4 for Photoelectrochemical Water Splitting.

As a photocathode with a band gap of about 1.8 eV, copper bismuthate (CuBi2O4) is a promising material for photoelectrochemical (PEC) water splitting. However, weak charge transfer capability and severe carrier recombination suppress the PEC performance of CuBi2O4. In this paper, the conductivity and carriers transport of CuBi2O4 are improved via introducing Zn2+ into the synthesis precursor of CuBi2O4, driving a beneficial 110 mV positive shift of onset potential in photocurrent. Detailed investigations demonstrate that the introduction of an appropriate amount of zinc leads to in situ segregation of ZnO which serves as an electron transport channel on the surface of CuBi2O4, forming heterojunctions. The synergistic effect of heterojunctions and doping simultaneously promotes the charge transfer and the carrier concentration. OCP experiment proves that ZnO/Zn-CuBi2O4 possesses better charge separation; the Mott-Schottky curve shows that the doping of Zn significantly enhances the carrier concentration; carrier lifetime calculated from time-resolved photoluminescence confirms faster extraction of carriers.

Selenization of NiCo2S4 Spinel Structure to Reduce the Charge Transfer Resistance for Supercapacitor Electrode

Due to the semiconductor properties and the weak charge transfer ability, the further application of spinellide material will be hindered in energy storage. Herein, the NiCo2S4 prepared by the two‐step method is modified adopting Se powder with different mass ratios under aqueous solvothermal conditions. Thanks to the selenide formed on the surface, the Se‐NiCo2S4‐10 sample exhibits a specific capacitance of 713 F g−1 at the current density of 1.0 A g−1, which is 2.6 times higher than that of pure NiCo2S4. Commercially, the assembled asymmetric supercapacitors Se‐NiCo2S4‐10//AC present an energy density of 25.13 Wh kg−1 under the power density of 753.9 W kg−1. This work shows that surface selenization has the effect of reducing charge transfer on spinel‐like nanomaterials, which provides a modified idea for the application of spinel materials in supercapacitor electrodes.

Catechol Sensing Performance of Pd-Functionalized Two-Dimensional Polyaramid: A DFT Investigation.

Catechol (Cc) molecule adsorption on a pristine and transition metal (TMs = Sc, Pd, and Cu)-functionalized two-dimensional polyaramid (2DPA) monolayer is systematically studied by the first-principles density functional theory method. The weak physisorption (-0.29 eV) and charge transfer of the Cc molecule with p-2DPA result in a very quick recovery time (150 μs), hindering the Cc sensing capability of p-2DPA. Although TM functionalization greatly improved the adsorption ability, the Pd-functionalized 2DPA was shown to be the best choice for Cc adsorption due to the reasonable adsorption energy of -1.39 eV and expedited charge transfer between the Cc and Pd atom. The change of band gap and, hence, the conductivity of the Pd-2DPA system in response to the adsorption of the Cc molecule demonstrate its higher sensitivity than that of p-2DPA. The work function sensitivity of Pd-2DPA upon the Cc adsorption is also investigated. In addition to the change in the electronic properties, the change in the optical properties of Pd-2DPA after Cc adsorption is also analyzed. The structural stability of Pd-2DPA is validated by performing ab initio molecular dynamics simulations at 300 K. The complete desorption of the Cc molecule from Pd-2DPA is attained by annealing the material at 550 K under visible light (τ = 5.4 s) and at 450 K under UV light (τ = 3.7 s). Moreover, the higher diffusion energy barrier of +1.35 eV confirmed that the functionalized Pd atoms did not diffuse through the crystal to form clusters. This study could lay a theoretical foundation for developing possibly new-generation sensors for detecting Cc molecules.

High-efficiency D-D-type wide bandgap polymer donor based on dibenzopyran unit

Pyran units as a six-membered heterocyclic nonaromatic containing one sp3 hybridized carbon and an oxygen have been widely employed to exploit donor and acceptor materials, and excellent power conversion efficiencies (PCEs) can be achieved for polymer solar cells (PSCs). In this work, a dibenzopyran (DBP) building block and a benzodithiophene (BDT) derivative as donor unit were utilized to successfully prepare a novel donor–donor (D-D)-type wide bandgap polymer PBDBP. The polymer PBDBP possesses an ultra-wide optical bandgap of 2.18 eV due to the weak intramolecular charge-transfer effect. Meanwhile, a low-lying HOMO energy of −5.41 eV is achieved, which is beneficial to realize a high Voc. Additionally, PBDBP also exhibits a complementary absorption with a narrow bandgap Y6 ranging from 300 to 950 nm, which can facilitate to improve light-harvesting ability for high Jsc. Finally, PBDBP:Y6 based device exhibits a high PCE of 11.43 % (Voc = 0.89 V, Jsc = 23.14 mA/cm2, and FF = 55.66 %). Our research indicates that the D-D-type polymer PBDBP based on dibenzopyran unit is a promising wide bandgap donor material for PSCs.

A ferrocene-based chemo-dosimeter for colorimetric and electrochemical detection of cyanide and its estimation in cassava flour.

A simple chemo-dosimeter VDP2 bearing a ferrocene moiety was designed, synthesized, and characterized, and exhibited both chromogenic and electrochemical responses selectively for CN- in H2O-DMSO (9 : 1, v/v) medium. The probe VDP2 showed an instantaneous color change from colorless to yellow with CN- that can readily be observed visually. The deprotonation of the benzimidazole -NH, followed by nucleophilic addition of CN- to the olefinic C-atom, as evidenced by 1H and 13C NMR titration experiments, caused the colorimetric and electrochemical responses. The mass spectral study, CV, FTIR and Mulliken charges computed well supported the proposed mechanism. The electrochemical limit of detection was calculated to be 72 nM. The results of DFT and TD-DFT calculations suggested that the colorless nature of the probe VDP2 is due to weak intramolecular charge transfer (ICT) transition and the yellow color of the VDP2+CN adduct is due to through-space ICT transition. Above all, the probe could be an ideal candidate for monitoring cyanide in water samples and cassava flour with practical significance. A simple and convenient colorimetric method was developed to determine cyanide content in cassava flour.

The effect of fluorination on the liquid crystal and optical behaviors of amphiphilic cyanostilbene-based mesogens

Three series of amphiphilic mesogens containing a cyanostilbene core with zero, one or two lateral fluorine atoms, which attach one polar glycerol group at one end and three lipophilic alkyl chains at the other end were synthesized by Suzuki coupling and Knoevenagel reactions. The thermodynamics, liquid crystalline and photophysical properties of these amphiphilic mesogens were evaluated by polarized optical microscopy, differential scanning calorimetry, small-angle X-ray diffraction, density functional theory calculation, absorption and emission spectra. The non-fluoro and mono-fluoro amphiphilic mesogens display a mesophase transition from hexagonal columnar phase to three-dimensional micellar cubic phase with Im3¯m lattice by the increase of temperature or the elongation of terminal lipophilic alkyl chains. The bi-fluoro amphiphilic mesogens can only self-organize into hexagonal columnar mesophase. Similar spectral properties and weak solvatochromism in these amphiphilic mesogens are observed attributed to the weak intramolecular charge transfer and weak influence of fluorine atom on the electronic properties in both ground and excited states. In addition, aggregation-induced emission behavior could be achieved in these amphiphilic mesogens due to the twisted molecular configuration. Therefore, complex self-assembly structures and interesting photophysical properties may be altered by varying the degree of fluorination of amphiphilic mesogens, which could promote the application of liquid crystalline materials.

Triphenylene-Based Emitters with Hybridized Local and Charge-Transfer Characteristics for Efficient Nondoped Blue OLEDs with a Narrowband Emission and a Small Efficiency Roll-Off.

Developing high-efficiency nondoped blue organic light-emitting diodes (OLEDs) with high color purity and low-efficiency roll-off is vital for display and lighting applications. Herein, we developed two asymmetric D-π-A blue emitters, PIAnTP and PyIAnTP, in which triphenylene is first utilized as a functional acceptor. The relatively weak charge transfer (CT) properties, rigid molecular structures, and multiple supramolecular interactions in PIAnTP and PyIAnTP can significantly enhance the fluorescence efficiency and suppress the structural relaxations to obtain a narrowband blue emission. The photophysical experiments and theoretical simulations reveal that they both exhibit a typical hybridized local and charge-transfer (HLCT) excited state and achieve high external quantum efficiency (EQE) via a "hot exciton" channel. As a result, PIAnTP- and PyIAnTP-based nondoped devices realize blue emission at 456 and 464 nm, corresponding to CIE coordinates of (0.16, 0.14) and (0.16, 0.19), narrow full width at half-maximums of 52 and 60 nm, and the high EQEs of 8.36 and 8.69%, respectively. More importantly, the PIAnTP- and PyIAnTP-based nondoped devices show small EQE roll-offs of only 5.9 and 2.4% at 1000 cd m-2, respectively. These results signify an advance in designing a highly efficient blue emitter for nondoped OLEDs.

Room-temperature organic magnetoresistance based on interfacial ground charge transfer state

We propose an organic magnetoresistance (OMR) based on the weak interfacial ground charge transfer (IGCT) state at m-MTDATA/Alq3 heterojunction. The maximum OMR reaches 13.2% at room temperature under an external magnetic field of 300 mT, which is well interpreted by the different roles of singlet and triplet IGCT states in hole transport. As demonstrated, the hole transport is blocked by singlet IGCT and passed through by triplet IGCT. By manipulating the Larmor frequencies of mixing singlet and triplet IGCT states through Δg mechanism under an external magnetic field, the hole current is modulated, thus generating OMR. Furthermore, OMR can be further enhanced to 15.4% at 300 mT and 27.9% at 1000 mT by inserting a thin BCP interlayer between m-MTDATA and Alq3 layers. This picture will help to implement a giant OMR with interfacial CT states in the future.

Phenoxazine and phenothiazine embedded Multi-Resonance emitters for highly efficient Pure-Red OLEDs with improved color purity

Multi-resonance (MR) emitters based on boron-nitrogen doped polycyclic aromatic hydrocarbons are the cutting-edge light-emitting materials for organic light-emitting diodes (OLEDs) due to their high photoluminescence quantum yield and narrowband emission spectra. Among all the widely-reported MR molecules, emitters showing pure-red emission are the least developed. The difficulty in designing pure-red MR emitters lies in the limit of the weak charge transfer nature of the MR framework, as well as the large molecular weight which may bring difficulty in vacuum sublimation process. Herein, through introducing the strong electron donating phenoxazine and phenothiazine moiety into the double-boron-based MR molecular skeleton, two novel MR emitters namely PXZBNO and PTZBNO were designed and synthesized. These two emitters exhibited pure-red emission with emission maxima up to 627 nm, small full-width at half-maximum (FWHM) of 45 nm. Red OLEDs based on PTZBNO demonstrated very high maximum external quantum efficiency (EQEmax) of 34.5%, together with very small efficiency roll-off. Meanwhile, PXZBNO-based purity pure-red OLEDs exhibited high color purity with color coordinates of (0.69, 0.31), which is approaching BT. 2020 standard.

Synthesis, LC self-assembly and photophysical behavior of stimuli responsive cyanostilbene-based hexacatenar mesogens with multicolour switching

A novel series of cyanostilbene-based hexacatenar mesogens consisting of two cyanostilbene units and one central pyridine in the π-conjugated rigid core were obtained by Suzuki coupling and Knoevenagel reactions. POM, DSC, SAXS, UV–vis spectrophotometer and fluorescence spectrophotometer were employed to explore the liquid crystalline, photophysical and stimuli responsive properties. All the biscyanovinyl diphenylpyridine-based hexacatenars can self-assemble into rectangular columnar phase with P2mm symmetry in bulk state. All the mesogens display weak solvatochromism due to the weak intramolecular charge transfer (ICT) and aggregation-induced enhanced emission (AIEE) due to non-planar structure and the long π-conjugated core. Temperature inducing hypochromatic shifts of fluorescence spectra, fluorescence quenching and the change in fluorescence color due to the phase transition and molecular planarization was well demonstrated. In addition, volatile acids could induce reversible changes of dual solid color, dual fluorescence color, fluorescence quantum yield and fluorescence lifetime owing to the protonation and deprotonation of pyridine. DFT analysis demonstrated that the protonation could induce more distinct molecular distortion and ICT, causing bathochromic-shifted absorption and emission spectra. Therefore, the introduction of different functional building blocks into liquid crystalline molecules is beneficial for the development of multifunctional materials.